High temperature explosives for downhole well applications

ABSTRACT

The present invention provides explosive compositions adapted for use in downhole well applications requiring high temperature explosives that may be exposed to elevated temperatures for extended periods of time.

FIELD OF THE INVENTION

[0001] The subject matter of the present invention relates to downholeexplosives. More specifically, the subject matter of the presentinvention relates to explosives for use in downhole wells forapplications requiring performance capability at high temperature and/orexposures at elevated temperatures for extended periods of time.

BACKGROUND OF THE INVENTION

[0002] Explosives are used in numerous downhole well applications. Anessential consideration in selecting explosives for use in downholeapplications, such as perforating operations, is that the explosiveshave a certain range of time and temperature in which the explosives arethermally stable. If the explosives are stretched beyond this range, theexplosives start to decompose, burn, or auto-detonate. Decomposition ofexplosives generally reduces their effectiveness and can cause a failuresuch as a misfire (a failure to detonate).

[0003] Failures of explosives are costly and often dangerous. Forexample, with regard to perforating applications, when a perforating gunstring is lowered to a desired depth but for some reason cannot beactivated, a mis-run has occurred. The mis-run requires that theperforating gun string be pulled out of the wellbore and replaced with anew gun string. Such replacement is both time consuming and expensive.Also, retrieving a mis-fired gun from a wellbore can be a hazardousoperation.

[0004] Because of the time-temperature range considerations regardingexplosives, in the past, use of explosive devices in downholeapplications has, in some instances, been precluded. In many operationswhere explosive actuation was desired (i.e., a device using a frangiblemember), alternative actuating means were selected because of the riskynature of the explosives within the high temperature environment. Inorder to use explosive devices in most downhole operations, it isimperative that the operating time for the explosives be increased for agiven temperature.

[0005] There is, therefore, a need for explosive compositions adaptedfor use in downhole well applications requiring explosives that may beexposed to elevated temperatures for extended periods of time. There isa need for such explosives having improved thermal stability for use inperforating applications for shape charges, boosters, detonating cords,and detonators. Additionally, there is a need for such explosives withimproved thermal stability for use in tubing and casing cutters,explosive-actuated sleeves, sonic or seismic fracing devices, settingdevices, explosive actuated sliding sleeves, valves or shuttles,breakable or frangible elements, tubing release devices, and actuatingdevices, for example.

SUMMARY OF THE INVENTION

[0006] One embodiment of the present invention provides identified hightemperature downhole explosives for use in downhole well devices. Suchexplosives, exhibit thermal stability characteristics suitable fordownhole applications.

[0007] Further scope of applicability of the present invention willbecome apparent from the detailed description presented hereinafter. Itshould be understood, however, that the detailed description and thespecific examples, while representing a preferred embodiment of thepresent invention, are given by way of illustration only, since variouschanges and modifications within the spirit and scope of the inventionwill become obvious to one skilled in the art from a reading of thefollowing detailed description.

BRIEF DESCRIPTION OF THE INVENTION

[0008] A full understanding of the present invention will be obtainedfrom the detailed description of the preferred embodiment presentedherein below, and the accompanying drawings, which are given by way ofillustration only and are not intended to be limitative of the presentinvention, and wherein:

[0009]FIG. 1 is a diagrammatic sketch of a downhole device that is partof a tool string within a well.

[0010]FIG. 2 is a cross-sectional view of an embodiment of the presentinvention for use in a typical shaped charge adapted for use in aperforating gun.

[0011]FIG. 3 is a cross-sectional view of another embodiment of thepresent invention for use in a typical tubing or casing cutter.

[0012]FIGS. 4a and 4 b are cross-sectional views of yet anotherembodiment of the present invention for use in a typical tubing releasemechanism.

[0013]FIG. 5 is a diagrammatic sketch of still another embodiment of thepresent invention for use in a sonic fracing device.

[0014]FIGS. 6a and 6 b are cross-sectional views of another embodimentof the present invention for use in an explosively set downholeapparatus. FIG. 6a displays the apparatus prior to explosive bonding,and FIG. 6b displays the apparatus after explosive bonding.

[0015]FIGS. 7a-7 c are cross-sectional views of another embodiment ofthe present invention for use in an apparatus for explosively opening aproduction valve.

[0016]FIG. 8 is a cross-sectional view of another embodiment of thepresent invention for use in an apparatus for actuating downhole tools.

DETAILED DESCRIPTION OF THE INVENTION

[0017] In the following detailed description of the subject matter ofthe present invention, identified high temperature downhole explosivesare principally described as being used in oil well applications. Suchapplications are intended for illustration purposes only and are notintended to limit the scope of the present invention. The identifiedhigh temperature downhole explosives can also be used to advantage inoperations within gas wells, water wells, injection wells, and controlwells. All such applications are intended to fall within the purview ofthe present invention. However, for purposes of illustration, theidentified high temperature downhole explosives will be described asbeing used for oil well applications.

[0018] As shown in FIG. 1, the identified high temperature downholeexplosives are principally described as being used in downhole welldevices that are part of a tool string. The identified high temperaturedownhole explosives of the present invention can be used for anyconceivable downhole device/application for which explosives aresuitable. More specifically, the identified high temperature downholeexplosives are particularly suited for applications requiring highperformance capability (i.e., jet production) combined with thermalstability at high temperature and/or exposures at elevated temperaturesfor extended periods of time. To achieve such performance, the hightemperature downhole explosives are characterized by minimal gas losscaused by exposure to elevated temperatures for extended periods oftime. The temperature/time suitability or performance ratings of theidentified high temperature downhole explosives provide a substantialbenefit in the ability of tools and equipment to perform well atelevated temperatures for extended periods of time.

[0019] One such identified high temperature downhole explosive isnonanitroterphenyl (NONA). The temperature/time suitability orperformance ratings of explosive components utilizing NONA, for example,exceed 500° F./1 hour, 460° F./100 hours, and 420° F./400 hours.Temperature Vacuum Stability Tests performed on NONA reveal that NONAsustains minimal gas loss at 392° F. even after exposure ofapproximately 90 days. Thus, NONA exhibits exceptional thermal stabilitysuitable for downhole applications.

[0020] Other identified high temperature downhole explosives exhibitingsimilar thermal stability qualities include, but are not limited to,octanitroterphenyl (ONT), pentanitrobenzophenone (PENCO),tetranitronaphthalene (TNN), tripicryltriazine (TPT), andtetranitrobenzotriazolo [1,2-a] benzotriazole (T-Tacot).

[0021] Table I to follow provides the results of a Temperature VacuumStability Test for the above mentioned identified high temperaturedownhole explosives. The table demonstrates the temperature/timesuitability at a temperature of 200° Celsius (392° Fahrenheit). Each ofthe above-mentioned identified high temperature downhole explosivesexhibit exceptional thermal stability at 200° Celsius. They sustainminimal gas loss while being exposed to the elevated temperature forextended period of time. TABLE I 200° Temperature Vacuum Stability TestsTime or exposure (days) 2 7 14 21 28 35 42 49 56 63 70 77 84 91 Totalgas evolved (cm³/g at STP) NONA .4 .8 1.1 1.6 2.0 2.3 2.8 3.2 3.6 3.94.3 4.7 5.1 5.4 ONT .9 1.3 1.4 1.5 1.6 1.7 1.9 1.9 2.0 2.1 2.3 2.4 2.52.6 PENCO .1 .2 .3 .4 .6 .6 .6 .7 .7 .9 1.0 1.1 1.2 1.4 TNN .3 .5 .6 .8.9 1.0 1.2 1.3 1.4 1.6 1.7 1.8 2.0 2.2 TPT .2 .2 .4 .4 .4 .4 .5 .5 .6 .7.9 1.0 1.0 1.1 T-tacot .1 .5 .9 1.3 1.6 1.9 2.1 2.5 3.0 3.5 3.9 4.3 4.85.3

[0022] The following identified high temperature downhole explosivesexhibit exceptional thermal stability at the elevated temperature of175° Celsius (347° F.). Such identified high temperature downholeexplosives include, but are not limited to, picrylaminotriazole (PATO),dinitropicrylbenzotriazole (BTX), dodecanitroquaterphenyl (DODECA),tripicrylmelamine (TPM), axobishexanitrobiphenyl (ABH),tetranitrobenzotriazolo [2,1-a] benzotriazole (Z-Tacot), potassium saltof hexanitrodiphenylamine (KHND), and tripicrylbenzene (TPB).

[0023] Table II to follow provides the results of a Temperature VacuumStability Test for the above mentioned identified high temperaturedownhole explosives. The table demonstrates the temperature/timesuitability at a temperature of 175° Celsius (347° Fahrenheit). Each ofthe above-mentioned identified high temperature downhole explosivesexhibit exceptional thermal stability at 175° Celsius. They sustainminimal gas loss while being exposed to the elevated temperature forextended period of time. TABLE II 175° Temperature Vacuum StabilityTests Time or exposure (days) 2 7 14 21 28 35 42 49 56 63 70 77 84 91Total gas evolved (cm³/g at STP) PATO .1 .4 .6 .7 .8 .9 1.1 1.2 1.3 1.41.4 1.4 1.4 1.5 BTX .2 .3 .4 .4 .5 .6 .7 .8 1.0 1.1 1.1 1.2 1.2 1.3DODECA .5 .7 .8 .9 .9 .9 1.0 1.0 1.0 1.1 1.2 1.3 1.4 1.4 TPM 1.5 2.0 2.32.6 2.9 3.3 3.7 4.1 4.5 4.9 5.2 5.5 5.9 6.7 ABH .4 .7 1.0 1.3 1.6 2.02.4 2.7 3.0 3.4 3.7 4.0 4.3 4.7 Z-Tacot .4 .5 .6 .7 .7 .7 .7 .7 .8 .91.0 1.1 1.4 1.7 KHND .1 .4 .5 .7 .8 1.0 1.1 1.3 1.4 1.6 1.8 2.0 2.2 2.4TPB .1 .1 .1 .1 .1 .1 .2 .2 .2 .2 .2 .2 .3 .3

[0024] The following identified high temperature downhole explosivesexhibit exceptional thermal stability at the elevated temperature of150° Celsius (302° F.). Such identified high temperature downholeexplosives include, but are not limited to, dipicramide (DIPAM),hexanitroazobenzene (HNAB), bis-hexanitroazobenzene (bis-HNAB),hexanitrobiphenyl (HNBP), dipicrylbenzobiatriazoledione (DPBT),dipicrylpyromellitude (DPPM), hexanitrodiphenylsulfone (HNDS), and bis[picrylazo] dinitropyridine (PADP-I).

[0025] Table III to follow provides the results of a Temperature VacuumStability Test for the above mentioned identified high temperaturedownhole explosives. The table demonstrates the temperature/timesuitability at a temperature of 150° Celsius (302° Fahrenheit). Each ofthe above-mentioned identified high temperature downhole explosivesexhibit exceptional thermal stability at 150° Celsius. They sustainminimal gas loss while being exposed to the elevated temperature forextended period of time. TABLE III 150° Temperature Vacuum StabilityTests Time or exposure (days) 2 7 14 21 28 35 42 49 56 63 70 77 84 91Total gas evolved (cm³/g at STP) DIPAM .2 .4 .5 .5 .6 .7 .7 .8 .8 .9 .91.0 1.0 1.0 HNAB .1 .2 .2 .3 .3 .4 .4 .5 .5 .6 .6 .7 .7 .7 bis-HNAB .51.2 1.8 2.5 2.9 3.6 4.2 4.8 5.3 6.0 6.7 7.4 8.1 8.8 HNBP .2 .3 .3 .4 .4.5 .5 .5 .6 .6 .7 .7 .8 .8 DPBT .4 .7 .9 1.0 1.3 1.5 1.7 1.9 2.1 2.2 2.32.4 2.5 2.7 DPPM .3 .7 1.0 1.2 1.4 1.5 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2HNDS .1 .2 .2 .3 .3 .3 .4 .5 .5 .6 .7 .9 1.1 1.3 PADP-I 5.3 4.9 4.3 4.13.9 4.1 4.2 4.2 4.3 4.4 4.5 4.7 4.9 5.0

[0026] Other identified high temperature downhole explosives suitablefor downhole use include, but are not limited to, sodiumtetranitrocarbozole (NaTNC), hexanitrobibenzyl (HNBIB), tetranitrocarbazole (TNC), 3,6 diamino 1,2,4,5 tetrazene (DAT),2,6-diamino-3,5-dinitropyridino-1-oxide (DADNPO), octanitromacro cycle(ONM), 4,6 dinitrobenzofuroxan (ADNBF), 2,5-dipcryl-1,3,4-oxadiazole(DPO) and m-picrylpicramide (PIPA).

[0027] It is important to note that although several of the aboveidentified high temperature downhole explosives have been groupedaccording to their thermal stability at particular temperatures, suchgrouping is only for the purpose of discussion and not intended todefine the grouped explosives as equivalent to each other. Although theexplosives within the groupings share similar thermal characteristics,that does not translate into equivalent suitability for variousapplications. Other material properties used in determining suitabilityfor particular applications include impact sensitivity, density, cost,etc. Such other properties are not dependent upon the thermalcharacteristics of a particular explosive.

[0028] The following examples are illustrative of the numerous downholeapplications for which the identified high temperature downholeexplosives of the present invention are suitable. Such examples areintended for illustration purposes only and are not intended to limitthe scope of the present invention. The identified high temperaturedownhole explosives can be used to advantage in any downhole applicationutilizing explosives. All such applications are intended to fall withinthe purview of the present invention.

[0029] Referring to FIG. 2, a typical shaped charge adapted for use in aperforating gun is illustrated. The perforating gun is adapted to bedisposed in a wellbore. Some shaped charges are discussed in U.S. Pat.No. 4,724,767 to Aseltine issued Feb. 16, 1988; U.S. Pat. No. 5,413,048to Werner et al. issued May 9, 1995; and again in U.S. Pat. No.5,597,974 to Voreck, Jr. et al. issued Jan. 28, 1997. Each of the abovementioned disclosures are incorporated by reference into thisspecification.

[0030] In FIG. 2, the shaped charge includes a case 10, a main body ofexplosive material 12, which in the past has been, for example, RDX,HMX, PYX, or HNS packed against the inner wall of the case 10, a primer13 disposed adjacent the main body of explosive 12 that is adapted todetonate the main body of explosive 12 when the primer 13 is detonated,and a liner 14 lining the primer 13 and the main body of explosivematerial 12. The shaped charge also includes an apex 18 and a skirt 16.A detonating cord 20 contacts the case 10 of the shaped charge at apoint near the apex 18 of the liner 14 of the charge. When a detonationwave propagates within the detonating cord 20, the detonation wave willdetonate the primer 13. When the primer 13 is detonated, the detonationof the primer 13 will further detonate the main body of explosive 12 ofthe charge. In response to the detonation of the main body of explosive12, the liner 14 will form a jet 22 that will propagate along alongitudinal axis of the shaped charge. The jet 22 will perforate aformation penetrated by the wellbore.

[0031] In accordance with the present invention, it has been discoveredthat, when the main body of explosive 12 is comprised of one or moreidentified high temperature downhole explosives (NONA, PATO, BTX, DIPAM,PENCO, TNN, HNAB, TPM, ABH, bis-HNAB, DODECA, HNBP, Z-Tacot, T-Tacot,DPBT, DPPM, HNDS, KHND, ONT, TPB, TPT, PADP-I, NaTNC, HNBIB, TNC, DAT,DADNPO, ONM, ADNBF, DPO, or PIPA), is comprised of a mixture of one ormore identified high temperature downhole explosives and one or moreother explosive compounds, such as HNS, PYX, HMX, or is comprised of oneor more identified high temperature downhole explosives combined/mixedwith one or more of an energetic material and a fuel, and when theprimer 13 is carefully selected to be comprised of a sensitive explosivematerial, the shaped charge exhibits exceptional thermal stabilitycharacteristics.

[0032] In the past, the primer 13 had to be comprised of a specialexplosive material, other than the explosive material comprising themain body of explosive 12, because the explosive material comprising themain body of explosive 12, by itself, was generally not sensitive enoughto be included as part of the primer 13. Therefore, the primer 13 wascomprised of a special (highly sensitive) explosive material other thanthe explosive material comprising the main body of explosive 12 in orderfor the primer 13 to be detonated. However, in the present invention,identified high temperature downhole explosives such as DPO have beenfound to exhibit sensitivity characteristics suitable for use as theprimer 13. Table IV displays the results of an exploding foil initiation(EFI) test in which DPO was compared with compounds having similarexplosive properties. TABLE IV Impact Thermal Stability at 260° C.Sensitivity Explosive Cc/g/hr. (2 hr.) (cm) DPO 0.6 20 NONA 0.5 39 HNS0.5 45 2,5-dipicryl-3,4-dinitrofuran 0.8 at 230° C. 23

[0033] As is shown by the data of Table IV, the explosives havingsimilar thermal stability characteristics as DPO (HNS and NONA), are notas impact sensitive. Likewise, although 2,5-dipicryl-3,4-dinitrofuranhas a similar sensitivity as DPO, it is not as thermally stable. Thus,DPO has a suitable combination of thermal stability and sensitivity tobe useful not only as a main body of explosive 12, but also as a primer13 or booster. One skilled in the art will recognize that thoseexplosives suitable as both the main body of explosive 12 and as theprimer 13 enable shape charges to be comprised of a single type ofexplosive.

[0034] It should be noted, the impact sensitivity of high temperaturedownhole explosives is often a function of their particle size. As anexample, by reducing the particle size of a NONA sample, the impactsensitivity of NONA has been found to be as low as 18 cm. As aconsequence, one skilled in the art will recognize that NONA ofappropriate particle size exhibits thermal sensitivity characteristicssuitable for use as a primer 13 or a booster.

[0035]FIG. 3 illustrates a typical shaped charge adapted for use in atubing or casing cutter. The tubing or casing cutter is adapted to bedisposed in a wellbore for cutting or severing oil well tubing, drillstrings, casings, and the like. Typical tubing or casing cutters arediscussed in U.S. Pat. No. 3,057,295 to Christopher issued Oct. 9, 1962,U.S. Pat. No. 4,184,430 to Mock issued Jan. 22, 1980, and U.S. Pat. No.6,053,247 to Wesson et al. issued Apr. 25, 2000. Each of the abovementioned disclosures are incorporated by reference into thisspecification.

[0036] The shaped explosive charge 30 is mounted within the chamber 32of the cutter head of the tubing or casing cutter. The shaped chargeincludes a booster charge element 34 ignited by a detonating fuse 36.The ignited booster charge element 34, in turn, detonates the mainexplosive charge elements 38 and 40, which produce a radial jet. Theradial jet propagates outwardly to cut the surrounding tubing or casing.

[0037] In accordance with the present invention, it has been discoveredthat, when the main explosive charge elements 38 and 40 are comprised ofone or more identified high temperature downhole explosives, arecomprised of a mixture of one or more identified high temperaturedownhole explosives and one or more other explosive compounds, such asHNS, PYX, HMX, or are comprised of one or more identified hightemperature downhole explosives and one or more of an energetic materialand a fuel or an oxidizer, and when the booster charge element 34 iscarefully selected to be comprised of a sensitive explosive material,the shaped charge exhibits exceptional thermal stabilitycharacteristics.

[0038] As discussed above with regard to the shaped charges used inperforating guns described with reference to FIG. 2, generally thebooster charge element 34 is comprised of a special (highly sensitive)explosive material other than the identified high temperature downholeexplosives used for the main explosive charge elements 38 and 40.However, identified high temperature downhole explosives such as DPO canbe used to advantage as the booster charge element 34.

[0039] Similar to the tubing or casing cutters, FIGS. 4a and 4 billustrate a typical tubing release mechanism. The tubing releasemechanism is adapted to be disposed in a wellbore, and moreparticularly, connected between a perforating apparatus and a tubing forshattering a frangible breakup tube thereby automatically releasing theperforating apparatus from the tubing in response to a detonation wavepassing. A typical tubing release mechanism is discussed in U.S. Pat.No. 5,293,940 to Hromas et al. issued Mar. 15, 1994, the details ofwhich are incorporated by reference into this specification.

[0040] As shown in FIGS. 4a and 4 b, when the firing heads 50 a and 50 bare initiated, a detonation wave is initiated within the detonating cord52. The detonation wave 52 propagates through the firing head adapter54, transfer housing 56, release piston 58, frangible breakup tube 60,release mandrel 62, and bottom sub 64, shooting the perforating gun.When the detonation wave propagating in the detonation cord 52 passesthrough the frangible breakup tube 60, the resultant shock wave andpressure from the detonation wave shatters the frangible breakup tube60. The breakup tube 60 shatters into small pieces. As a result, therelease piston 58 is no longer supported and held in position by thebreakup tube 60. The pressure force pushing down on the release piston58 forces the release piston 58 down into the air chamber 46, whichsubsequently causes the release of the perforating gun.

[0041] In accordance with the present invention, it has been discoveredthat, when the detonation cord is comprised of one or more identifiedhigh temperature downhole explosives, is comprised of a mixture of oneor more identified high temperature downhole explosives and one or moreother explosive compounds, such as UNS, PYX, HMX, or is comprised of oneor more identified high temperature downhole explosives and one or moreof an energetic material and a fuel or an oxidizer, the detonating cord52 exhibits exceptional thermal stability characteristics.

[0042]FIG. 5 illustrates a sonic fracing mechanism. The tubing releasemechanism is adapted to be disposed in a wellbore, and moreparticularly, to increase formation permeability by creating sonic wavesthat crack loosen the formation interstices. A typical sonic fracingmechanism is discussed in U.S. Pat. No. 5,293,940 to Beard issued Aug.27, 1985, the details of which are incorporated by reference into thisspecification.

[0043] As shown in FIG. 5, the sonic fracing mechanism has a series ofcylinders 70 mounted in a tubular housing 72. An explosive is containedin a combustion chamber 74 within each cylinder. The first cylinder isfired, causing an explosion, the shock of which is transmitted throughthe ambient fluid into the formation. After a preselected interval,another cylinder is fired, with slightly greater shock, and the thirdfiring to follow being greater than the second. The force of therespective explosions creates a wave in the formation, which movesoutwardly away from the casing until the force of the explosion isexhausted; then the wave returns through the formation to the casing,where it will be met by the next, and greater explosion, creating agreater wave, thus effecting the washing action clearing passageways forthe flow of production fluid.

[0044] In accordance with the present invention, it has been discoveredthat, when the explosive contained within the combustion chamber iscomprised of one or more identified high temperature downholeexplosives, is comprised of a mixture of one or more identified hightemperature downhole explosives and one or more other explosivecompounds, such as HNS, PYX, HMX, or is comprised of one or moreidentified high temperature downhole explosives combined/mixed with oneor more of an energetic material and a fuel or an oxidizer, thecombustion chamber exhibits exceptional thermal stabilitycharacteristics.

[0045]FIGS. 6a and 6 b illustrate an explosively set downhole apparatus.Setting apparatus are used for the placement or setting of boreholeapparatus such as packers, casing bore receptacles, bridge plugs, casingpatches, and liner hangers within the casing of a well bore through theexplosive bonding of such apparatus to the interior of the casing.Typical explosively set downhole apparatus are discussed in U.S. Pat.No. 4,662,450 to Haugen issued May 5, 1987, and U.S. Pat. No. 5,447,202to Littleford, the details of which are incorporated by reference intothis specification.

[0046] Referring to FIG. 6a, detonation of the explosive charge 80creates a radial shock wave that drives fixation element 82 radiallyoutward into the casing 84, as shown in FIG. 6b . The fixation element82 is explosively welded thereto or bonded therewith the casing 84.

[0047] In accordance with the present invention, it has been discoveredthat, when the explosive charge 80 is comprised of one or moreidentified high temperature downhole explosives, is comprised of amixture of one or more identified high temperature downhole explosivesand one or more other explosive compounds, such as HNS, PYX, HMX, or iscomprised of one or more identified high temperature downhole explosivescombined/mixed with one or more of an energetic material and a fuel oran oxidizer, the explosive charge 80 exhibits exceptional thermalstability characteristics.

[0048]FIGS. 7a-7 c illustrate an apparatus for explosively opening aproduction valve. More particularly, the figures illustrate an apparatusadapted to be disposed in a wellbore having a frangible breakup elementthat is adapted to shatter into a multitude of pieces when a detonationwave passes therethrough. A piston is supported by the frangible breakupelement such that when the frangible breakup element shatters, thepiston moves a predetermined distance, thus opening the productionvalve. An example of an apparatus for explosively opening a productionvalve is discussed in U.S. Pat. No. 5,318,126 to Edwards et al. issuedJun. 7, 1994, the details of which are incorporated by reference intothis specification.

[0049] Referring to FIGS. 7a-7 c, a detonation cord 90 is disposedwithin a series of frangible breakup elements 92 such that a detonationwave propagated by the detonation cord 90 acts to shatter the breakupelements 92. Shattering of the elements 92 removes the support for thepiston 94 which is then free to move downwardly in response to eithertubing pressure or rathole pressure or both. Once the piston 94 movesdownward a predetermined distance, the piston acts to open theproduction valve.

[0050] In accordance with the present invention, it has been discoveredthat, when the detonating cord 90 is comprised of one or more identifiedhigh temperature downhole explosives, a mixture of one or moreidentified high temperature downhole explosives with one or more otherexplosive compounds, such as HNS, PYX, HMX, or one or more identifiedhigh temperature downhole explosives combined/mixed with one or more ofan energetic material and a fuel or an oxidizer, the detonating cord 90exhibits exceptional thermal stability characteristics.

[0051]FIG. 8 illustrates an apparatus for actuating downhole tools byfiring an explosive charge to generate an operating pressure. An exampleof an apparatus for explosively actuating downhole tools is discussed inU.S. Pat. No. 5,316,087 to Manke et al. issued May 31, 1994, the detailsof which are incorporated by reference into this specification.

[0052] As further described below, the power piston 106 reciprocates upand down imparting linear movement of the power mandrel 108 to operatethe operating element 110. The operating element 110 may be of manydifferent varieties corresponding to the various tools within thetesting string. For example, the operating element 110 may be a rotatingball valve type element of a formation tester valve having an operatingmechanism substantially like that shown in U.S. Pat. No. 3,856,085 toHolden et al., the details of which are incorporated herein byreference.

[0053] As another example, the operating element 110 could be a slidingsleeve valve of a reclosable reverse circulation valve having anassociated operating mechanism substantially like that shown in U.S.Pat. No. 4,113,012 to Evens et al., the details of which areincorporated herein by reference.

[0054] The operating element 110 may also be a closing element of anyone of several types of known sampling apparatus. Also, a multi-modeoperating element could be used substantially like that shown in U.S.Pat. No. 4,711,305 to Ringgenberg, the details of which are incorporatedherein by reference.

[0055] Referring to FIG. 8, a plurality of explosive charges arecontained within the housing 102 and communicated with the upper andlower power chamber portions 114 and 116. The explosive charges (118A,118B, 118C, and 118D) are electrically fired explosive charges. When anyone of the explosive charges 118 is fired, it generates hightemperature, high pressure gases within its associated power chamberportion 114, 116 which acts to move the power piston 106 within thepower chamber 112.

[0056] In accordance with the present invention, it has been discoveredthat, when the explosive charges 118 are comprised of one or moreidentified high temperature downhole explosives, are comprised of amixture of one or more identified high temperature downhole explosivesand one or more other explosive compounds, such as HNS, PYX, HMX, or arecomprised of one or more identified high temperature downhole explosivescombined/mixed with one or more of an energetic material and a fuel oran oxidizer, the explosive charges 118 exhibit exceptional thermalstability characteristics.

[0057] As discussed above, and as one skilled in the art will recognize,the identified high temperature downhole explosives that comprise thesubject matter of the present invention can be used in a great number ofdownhole applications. In perforating operations, the identified hightemperature downhole explosives can be used not only as the main body ofexplosive of the shape charge, but can also be used for boosters,detonating cords, and detonators, for example. Additionally, theidentified high temperature downhole explosives of the present inventioncan also be used to advantage in applications involving tubing andcasing cutters, explosive-actuated sleeves, valves or shuttles,breakable or frangible elements, or sonic or seismic source devices, forexample.

[0058] It should be noted that the above discussed application of usefor the identified high temperature downhole explosives of the presentinvention are intended for illustration purposes only, and are notintended as limitations to the scope of the present invention. Oneskilled in the art will recognize that the identified high temperaturedownhole explosives are not limited in application. The identified hightemperature downhole explosives are useful in any number of downholewells and any number of applications requiring performance capability athigh temperatures and/or exposures at elevated temperatures for extendedperiods of time.

[0059] The invention being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following non-limiting claims.

We claim:
 1. Explosives for use in downhole well devices, comprising oneor more identified high temperature downhole explosives.
 2. Theexplosives of claim 1, wherein the one or more identified hightemperature downhole explosives comprise NONA.
 3. The explosives ofclaim 1, wherein the one or more identified high temperature downholeexplosives are selected from NONA, PENCO, TNN, T-Tacot, ONT, and TPT. 4.The explosives of claim 1, wherein the one or more identified hightemperature downhole explosives are selected from PATO, BTX, TPM, ABH,DODECA, Z-Tacot, KHND, and TPB.
 5. The explosives of claim 1, whereinthe one or more identified high temperature downhole explosives areselected from DIPAM, HNAB, bis-HNAB, HNBP, DPBT, DPPM, HNDS, and PADP-I.6. The explosives of claim 1, wherein the one or more identified hightemperature downhole explosives are selected from NaTNC, HNBIB, TNC,DAT, DADNPO, ONM, ADNBF, DPO, and PIPA.
 7. The explosives of claim 1,further comprising one or more other explosive compounds.
 8. Theexplosives of claim 7, wherein the one or more other explosive compoundsare selected from HNS, PYX, and HMX.
 9. The explosives of claim 1,further comprising one or more of an energetic material and a fuel. 10.The explosives of claim 1, further comprising one or more of anenergetic material and an oxidizer.
 11. The explosives of claim 1,wherein the downhole well devices are selected from perforating guns,perforating devices, tubing or casing cutters, tubing releasemechanisms, fracing mechanisms, setting apparatus, explosively openingproduction valves, and downhole tool actuators.
 12. The explosives ofclaim 1, wherein the downhole well devices are part of a tool string.13. The explosives of claim 1, wherein the downhole well devices areshaped charges.
 14. The explosives of claim 1, wherein the one or morehigh temperature downhole explosives are used in the downhole welldevices for explosive components selected from shaped charges,detonators, detonating cords, boosters, and primers.
 15. A downholedevice having an explosive component, comprising: one or more identifiedhigh temperature downhole explosives.
 16. The downhole device of claim15, wherein the one or more identified high temperature downholeexplosives comprise NONA.
 17. The downhole device of claim 15, whereinthe one or more identified high temperature downhole explosives areselected from NONA, PENCO, TNN, T-Tacot, ONT, and TPT.
 18. The downholedevice of claim 15, wherein the one or more identified high temperaturedownhole explosives are selected from PATO, BTX, TPM, ABH, DODECA,Z-Tacot, KHND, and TPB.
 19. The downhole device of claim 15, wherein theone or more identified high temperature downhole explosives are selectedfrom DIPAM, HNAB, bis-HNAB, HNBP, DPBT, DPPM, HNDS, and PADP-I.
 20. Thedownhole device of claim 15, wherein the one or more identified hightemperature downhole explosives are selected from NaTNC, HNBIB, TNC,DAT, DADNPO, ONM, ADNBF, DPO, and PIPA.
 21. The downhole device of claim15, wherein the explosive component further comprises one or more otherexplosive compounds.
 22. The downhole device of claim 21, wherein theone or more other explosive compounds are selected from HNS, PYX, andHMx.
 23. The downhole device of claim 15, wherein the explosivecomponent further comprises one or more of an energetic material and afuel.
 24. The downhole device of claim 15, wherein the explosivecomponent further comprises one or more of an energetic material and anoxidizer.
 25. The downhole device of claim 15, wherein the device isselected from perforating guns, perforating devices, tubing or casingcutters, tubing release mechanisms, fracing mechanisms, settingapparatus, explosively opening production valves, and downhole toolactuators.
 26. The downhole device of claim 15, wherein the device ispart of a tool string.
 27. The downhole device of claim 15, wherein theexplosive component is selected from shaped charges, detonators,detonating cords, boosters, and primers.
 28. A shaped charge made by aprocess, comprising: (a) inserting a main body of explosive into a case,the main body of explosive comprising one or more identified hightemperature downhole explosives; and (b) inserting a liner over the mainbody of explosive.
 29. The shaped charge made by the process of claim28, wherein the one or more defined high temperature downhole explosivescomprise NONA.
 30. The shaped charge made by the process of claim 28,wherein the one or more identified high temperature downhole explosivesare selected from NONA, PENCO, TNN, T-Tacot, ONT, and TPT.
 31. Theshaped charge made by the process of claim 28, wherein the one or moreidentified high temperature downhole explosives are selected from PATO,BTX, TPM, ABH, DODECA, Z-Tacot, KHND, and TPB.
 32. The shaped chargemade by the process of claim 28, wherein the one or more identified hightemperature downhole explosives are selected from DIPAM, HNAB, bis-HNAB,HNBP, DPBT, DPPM, HNDS, and PADP-I.
 33. The shaped charge made by theprocess of claim 28, wherein the one or more identified high temperaturedownhole explosives are selected from NaTNC, HNBIB, TNC, DAT, DADNPO,ONM, ADNBF, DPO, and PIPA.
 34. The shaped charge made by the process ofclaim 28, wherein the main body of explosives further comprises one ormore other explosive compounds.
 35. The shaped charge of claim 34,wherein the one or more other explosive compounds are selected from HNS,PYX, and HMX.
 36. The shaped charge made by the process of claim 28,wherein the main body of explosives further comprises one or more of anenergetic material and a fuel.
 37. The shaped charge made by the processof claim 28, further comprising a primer inserted into the case adaptedfor detonating the main body of explosive.
 38. The shaped charge ofclaim 37, wherein the primer comprises NONA.
 39. The shaped charge ofclaim 37, wherein the primer comprises one or more identified hightemperature downhole explosives.
 40. The shaped charge of claim 37,wherein the primer is an explosive compound more sensitive than the oneor more identified high temperature downhole explosives.
 41. A method ofusing one or more high temperature downhole explosives in a well, themethod comprising: (a) providing a downhole device having one or moreidentified high temperature downhole explosives. (b) conveying thedownhole device into the well.
 42. The method of claim 41, wherein theidentified high temperature downhole explosives comprise NONA.
 43. Themethod of claim 41, wherein the one or more identified high temperaturedownhole explosives are selected from NONA, PENCO, TNN, T-Tacot, ONT,and TPT.
 44. The method of claim 41, wherein the one or more identifiedhigh temperature downhole explosives are selected from PATO, BTX, TPM,ABH, DODECA, Z-Tacot, KHND, and TPB.
 45. The method of claim 41, whereinthe one or more identified high temperature downhole explosives areselected from DIPAM, HNAB, bis-HNAB, HNBP, DPBT, DPPM, HNDS, and PADP-I.46. The method of claim 41, wherein the one or more identified hightemperature downhole explosives are selected from NaTNC, HNBIB, TNC,DAT, DADNPO, ONM, ADNBF, DPO, and PIPA.
 47. The method of claim 41,further comprising the step of combining the one or more identified hightemperature downhole explosives with matter selected from one or moreother explosives and one or more of an energetic material and a fuel.